Utilizing metagenomic next-generation sequencing for diagnosis and lung microbiome probing of pediatric pneumonia through bronchoalveolar lavage fluid in pediatric intensive care unit: results from a large real-world cohort.

Background: Metagenomic next-generation sequencing (mNGS) is a powerful method for pathogen detection in various infections. In this study, we assessed the value of mNGS in the pathogen diagnosis and microbiome analysis of pneumonia in pediatric intensive care units (PICU) using bronchoalveolar lavage fluid (BALF) samples. Methods: A total of 104 pediatric patients with pneumonia who were admitted into PICU between June 2018 and February 2020 were retrospectively enrolled. Among them, 101 subjects who had intact clinical information were subject to parallel comparison of mNGS and conventional microbiological tests (CMTs) for pathogen detection. The performance was also evaluated and compared between BALF-mNGS and BALF-culture methods. Moreover, the diversity and structure of all 104 patients' lung BALF microbiomes were explored using the mNGS data. Results: Combining the findings of mNGS and CMTs, 94.06% (95/101) pneumonia cases showed evidence of causative pathogenic infections, including 79.21% (80/101) mixed and 14.85% (15/101) single infections. Regarding the pathogenesis of pneumonia in the PICU, the fungal detection rates were significantly higher in patients with immunodeficiency (55.56% vs. 25.30%, P =0.025) and comorbidities (40.30% vs. 11.76%, P=0.007). There were no significant differences in the α-diversity either between patients with CAP and HAP or between patients with and without immunodeficiency. Regarding the diagnostic performance, the detection rate of DNA-based BALF-mNGS was slightly higher than that of the BALF-culture although statistically insignificant (81.82% vs.77.92%, P=0.677) and was comparable to CMTs (81.82% vs. 89.61%, P=0.211). The overall sensitivity of DNA-based mNGS was 85.14% (95% confidence interval [CI]: 74.96%-92.34%). The detection rate of RNA-based BALF-mNGS was the same with CMTs (80.00% vs 80.00%, P>0.999) and higher than BALF-culture (80.00% vs 52.00%, P=0.045), with a sensitivity of 90.91% (95%CI: 70.84%-98.88%). Conclusions: mNGS is valuable in the etiological diagnosis of pneumonia, especially in fungal infections, and can reveal pulmonary microecological characteristics. For pneumonia patients in PICU, the mNGS should be implemented early and complementary to CMTs.

Metagenomic next-generation sequencing of bronchoalveolar lavage fluid from children with severe pneumonia in pediatric intensive care unit.

Background: Severe pneumonia due to lower respiratory tract infections (LRTIs) is a significant cause of morbidity and mortality in children. Noninfectious respiratory syndromes resembling LRTIs can complicate the diagnosis and may also make targeted therapy difficult because of the difficulty of identifying LRTI pathogens. In the present study, a highly sensitive metagenomic next-generation sequencing (mNGS) approach was used to characterize the microbiome of bronchoalveolar lavage fluid (BALF) in children with severe lower pneumonia and identify pathogenic microorganisms that may cause severe pneumonia. The purpose of this study was to use mNGS to explore the potential microbiomes of children with severe pneumonia in a PICU. Methods: We enrolled patients meeting diagnostic criteria for severe pneumonia admitted at PICU of the Children's Hospital of Fudan University, China, from February 2018 to February 2020. In total, 126 BALF samples were collected, and mNGS was performed at the DNA and/or RNA level. The pathogenic microorganisms in BALF were identified and correlated with serological inflammatory indicators, lymphocyte subtypes, and clinical symptoms. Results: mNGS of BALF identified potentially pathogenic bacteria in children with severe pneumonia in the PICU. An increased BALF bacterial diversity index was positively correlated with serum inflammatory indicators and lymphocyte subtypes. Children with severe pneumonia in the PICU had the potential for coinfection with viruses including Epstein-Barr virus, Cytomegalovirus, and Human betaherpesvirus 6B, the abundance of which was positively correlated with immunodeficiency and pneumonia severity, suggesting that the virus may be reactivated in children in the PICU. There was also the potential for coinfection with fungal pathogens including Pneumocystis jirovecii and Aspergillus fumigatus in children with severe pneumonia in the PICU, and an increase in potentially pathogenic eukaryotic diversity in BALF was positively associated with the occurrence of death and sepsis. Conclusions: mNGS can be used for clinical microbiological testing of BALF samples from children in the PICU. Bacterial combined with viral or fungal infections may be present in the BALF of patients with severe pneumonia in the PICU. Viral or fungal infections are associated with greater disease severity and death.

Clinical characteristics and outcomes of children with prolonged mechanical ventilation in PICUs in mainland China: A national survey.

OBJECTIVE: The number of children on prolonged mechanical ventilation (PMV) in pediatric intensive care units (PICU) has increased markedly, but little is known about the situation in mainland China. We carried out a multicenter retrospective investigation to describe the clinical characteristics and prognosis of Chinese children receiving long-term ventilation in the PICU. METHODS: A retrospective study was performed in 11 PICUs. All participating patients with prolonged mechanical ventilation in the study were retrospectively identified and included from cases admitted to PICUs between January 1, 2017 and December 31, 2019. RESULTS: A total of 346 children diagnosed with prolonged mechanical ventilation were included in the study. Overall, 240 survived and were discharged from PICU, 55 died in hospital, and 51 withdrew from mechanical ventilation support with 41 died after discharge. Lower airway diseases were the most common underlying causes (41.6%), followed by central nervous system diseases (29.5%), and neuromuscular diseases (13.3%). Most children (327, 94.5%) received invasive mechanical ventilation (IMV) and only 19 (5.5%) children received noninvasive ventilation (NIV). The median time of tracheostomy after ventilation was 21 days (15-35). Children with tracheostomy had lower mortality with longer PICU stay compared with patients without tracheostomy. Children who underwent tracheostomy were more likely to have central nervous system diseases and neuromuscular diseases. CONCLUSION: This study showed a steady increase in the number of children receiving prolonged mechanical ventilation during the study period in Chinese PICUs with distinct clinical characteristics and outcomes. A better community-based care for PMV children is needed in mainland China.

The application of metagenomic next-generation sequencing for Angiostrongylus eosinophilic meningitis in a pediatric patient: A case report.

Background: Angiostrongylus eosinophilic meningitis (AEM) is a rare yet emerging disease caused by Angiostrongylus cantonensis infection. Its atypical symptoms may delay the diagnosis and cause fatal outcomes, especially in the early stages of infection and among children. Case presentation: Here we reported the use of metagenomic next-generation sequencing (mNGS) to facilitate the diagnosis and treatment of an 8-year-old boy with severe A. cantonensis infection. The mNGS tests consistently identified the infection of A. cantonensis prior to the detection by the immunologic method and confirmed it as AEM. Owing to the multidisciplinary team (MDT)-administrated treatments and close disease monitoring based on regular clinical tests and sequential mNGS tests, the patients eventually fully recovered from severe infectious conditions. Conclusion: This case demonstrated the advantages of mNGS for early diagnosis of AEM in pediatric patients, highlighting its application for pan-pathogen detection, as well as disease monitoring for severe A. cantonensis infection.

Predictive Value of Diaphragmatic Ultrasonography for the Weaning Outcome in Mechanically Ventilated Children Aged 1-3 Years.

Background: There are estimated 20% of mechanically ventilated patients having difficulty in weaning from the ventilators, and the weaning process accounts for 40% of the whole ventilation time. Reliable tools are urgently needed to estimate the weaning outcome. Diaphragmatic ultrasonography, as a relatively good predictive method for the adults, was measured in this study, assessing the value of each indicator of diaphragmatic ultrasonography to predict the outcomes of ventilator weaning from mechanically ventilated children of 1-3 years old. Methods: Between November 2018 and November 2019, children who were mechanically ventilated and ready for weaning in the pediatric intensive care unit (PICU) were enrolled in the study. Diaphragmatic ultrasonography was performed to the children to measure the right diaphragm excursion (DE), contraction velocity, thickness, and diaphragm thickening fraction (DTF), which were recorded followed by spontaneous breathing trial (SBT). The receiver operator characteristic (ROC) curves were also used to assess the value of each indicator to predict the weaning outcome. Results: During this study period, a total of 72 children were enrolled, and of them, 56 children passed the weaning process, while 16 children failed. There were significant differences in DE, contraction velocity, thickness, and DTF parameters between the weaning success group and the failure group. The areas under the ROC curves (AUC) and the optimal threshold of the above indicators were as follows: 0.72 and 8.08 mm for DE, 0.71 and 26.1% for right DTF (DTFR), 0.71 and 20.7% for left DTF (DTFL), 0.78 and 14.8% for minimum DTF (DTFMIN), 0.79 and 26.1% for maximum DTF (DTFMAX), 0.71 and 1.24 mm for maximum diaphragm thickness at the end of inspiration (DteiMAX), and 0.65 and 10.0 mm/s for contraction velocity. Conclusion: Diaphragmatic ultrasonography is feasible in guiding ventilator weaning, and the indicators of DE, DTF, and DteiMAX guide the weaning more accurately. Among them, DTF may act as a more reliable predictor of weaning by avoiding the influence of diaphragm development in children.

Metagenomic Next-Generation Sequencing of Bloodstream Microbial Cell-Free Nucleic Acid in Children With Suspected Sepsis in Pediatric Intensive Care Unit.

Bloodstream infection is a life-threatening complication in critically ill patients. Multi-drug resistant bacteria or fungi may increase the risk of invasive infections in hospitalized children and are difficult to treat in intensive care units. The purpose of this study was to use metagenomic next-generation sequencing (mNGS) to understand the bloodstream microbiomes of children with suspected sepsis in a pediatric intensive care unit (PICU). mNGS were performed on microbial cell-free nucleic acid from 34 children admitted to PICU, and potentially pathogenic microbes were identified. The associations of serological inflammation indicators, lymphocyte subpopulations, and other clinical phenotypes were also examined. mNGS of blood samples from children in PICU revealed potential eukaryotic microbial pathogens. The abundance of Pneumocystis jirovecii was positively correlated with a decrease in total white blood cell count and immunodeficiency. Hospital-acquired pneumonia patients showed a significant increase in blood bacterial species richness compared with community-acquired pneumonia children. The abundance of bloodstream bacteria was positively correlated with serum procalcitonin level. Microbial genome sequences from potential pathogens were detected in the bloodstream of children with suspected sepsis in PICU, suggesting the presence of bloodstream infections in these children.

Modeling Approach to Optimizing Dose Regimen of Vancomycin for Chinese Pediatric Patients with Gram-Positive Bacterial Infections.

The aim of this study was to establish the population pharmacokinetics (PK) model of Vancomycin for Chinese pediatric patients which can extrapolate to whole age periods by bridging the published adult population PK model and the established pediatric population PK model. The final consolidated population PK model was used to explore the correlation of pharmacokinetics/pharmacodynamics (PK/PD) indices and efficacy of vancomycin and to provide evidence for the optimized regimen of vancomycin in Chinese pediatric patients with Gram-positive bacterial infection. 108 pediatric patients with Gram-positive infections from 2 pediatric hospitals in China in the first period of the prospective multi-center vancomycin clinical observational study were enrolled to establish the population PK model. A one-compartment population PK model was established and validated. The correlation between vancomycin PK/PD indices [trough concentration (Cmin), peak concentration (Cmax), 0-24 h area under the curve (AUC0-24) and the area under the curve to minimum inhibitory concentration ratio (AUC0-24/MIC)] and the overall clinical outcomes (clinical efficacy and microbiological efficacy) in Chinese pediatric patients were evaluated. There is no significant correlation between PK/PD indices and clinical efficacy or microbiological efficacy. Considering the high clinical effective rate (>90%) and median AUC0-24/MIC values of 200-300, Chinese pediatric patients with Gram-positive bacterial infection may be suitable for lower AUC0-24/MIC target value compared to the target value of 400-600 recommended by IDSA guideline. Different optimal dose regimen of vancomycin for Chinese pediatric patients should be considered. Further evaluation in more prospective studies will be needed.

A Prospective Multicenter Clinical Observational Study on Vancomycin Efficiency and Safety With Therapeutic Drug Monitoring.

Background: Vancomycin is a first-line antibiotic used for the treatment of severe gram-positive bacterial infections. Clinical guidelines recommend that the vancomycin trough concentration be 10-15 mg/L for regular infections and 15-20 mg/L for severe infections. We investigated whether increasing the vancomycin concentration would result in better clinical outcomes with sustainable adverse effects (AEs) in the Chinese population. Methods: A prospective, open, multicenter clinical observational study was performed in patients with gram-positive bacterial infections from 13 teaching hospitals. Patients received vancomycin therapeutic drug monitoring. Clinical, microbiological, and laboratory data were collected. Results: In total, 510 patients were enrolled, and 470 were evaluable, of whom 370 were adults and 100 were children; 35.53% had methicillin-resistant Staphylococcus aureus infections (vancomycin 50% minimum inhibitory concentration [MIC50] = 1, 90% minimum inhibitory concentration [MIC90] = 1), and 23.19% had Enterococcus species infections (vancomycin MIC50 = 1, MIC90 = 2). The average trough concentration was 10.54 ± 8.08 mg/L in adults and 6.74 ± 8.93 mg/L in children. The infection was eradicated in 86.22% of adults and 96% of children. Thirty-six vancomycin-related nephrotoxicity cases were reported in the enrolled population. No severe AEs or deaths were related to vancomycin therapy. Logistic regression analysis showed that trough concentration had no relationship with clinical outcomes (adults P = .75, children P = .68) but was correlated with adult nephrotoxicity (P < .0001). Vancomycin trough concentration had an applicable cut point at 13 mg/L. Conclusions: Our study shows that vancomycin trough concentration has no statistical correlation with clinical outcomes, and is an indicator of nephrotoxicity in the observed population. We found no evidence that increasing vancomycin trough concentration to 15-20 mg/L can benefit Chinese patients with complicated infections. Clinical Trials Registration: ChiCTR-OPC-16007920.

[Application of noninvasive ventilation in children with acute respiratory distress syndrome].

Acute respiratory distress syndrome (ARDS) is a common critical illness in children and has high incidence and mortality rates among critically ill pediatric patients. Noninvasive ventilation has become a common treatment method for ARDS because of its unique features. This article reviews the research status in the application of noninvasive ventilation in children with ARDS.

Neuroprotective effects of pinocembrin on ischemia/reperfusion-induced brain injury by inhibiting autophagy.

BACKGROUND: Cerebral ischemia/reperfusion (I/R) injury is a common pathological process after cardiac arrest, shock and acute cerebral infarction recanalization, which causes serious injury in brain function. Pinocembrin (Pino), a natural flavonoid at the highest concentration in propolis, exhibited a variety of biological effects, including antitumor, antimicrobial and anti-inflammatory activities. However, the effects of Pino on brain injured after I/R and the mechanisms of its neuroprotective effects remain elusive. METHODS: In the present study, we used I/R model rats underwent transient cerebral ischemia inducing by four-vessel occlusion and reperfusion. Pino alone or in combination with autophagy inducer rapamycin (RAPA) was administered to I/R rats. The behavior and cognitive function were evaluated by open field test and Morris water maze test. HE staining was used to determine the survival of hippocampus CA1 pyramidal cells. Three key proteins of autophagy, LC3, Beclin1 and p62, were detected by Western blot. RESULTS: Our results showed that Pino could significantly reduce the damage of hippocampus CA1 pyramidal neurons and alleviate the impairments of behavior and cognitive function in I/R rats. Pino also decreased the expression of LC3II and Beclin1 and increased the level of p62 in hippocampus CA1 of I/R rats. In addition, Pino also decreased RAPA-induced neuronal damage and excessive activation of autophagy in I/R rats. CONCLUSIONS: Taken together, these results suggested that Pino could protect the brain injury induced by I/R and the potential mechanisms might attribute to inhibition of autophagy activity.

Puerarin attenuates locomotor and cognitive deficits as well as hippocampal neuronal injury through the PI3K/Akt1/GSK-3ß signaling pathway in an in vivo model of cerebral ischemia.

Ischemic stroke causes irreversible damage to the brain. The hippocampus is a vulnerable region and plays an important role in cognition and locomotor activity. Puerarin is a phytoestrogen that has beneficial effects in treating neurological disorders. How puerarin protects against hippocampal injury and its molecular mechanisms remain to be elucidated. Transient global brain ischemia was induced by 4-vessel occlusion in adult male Sprague-Dawley rats. The rats were pretreated with puerarin alone or together with LY294002 (an PI3K inhibitor) before ischemia/reperfusion (I/R). The open- and closed-field tasks and Morris water maze (MWM) test were used to assess the effects of puerarin on anxiety-like behavioral and cognitive impairment following I/R. Hematoxylin-eosin staining(HE) was used to examine the survival of hippocampal CA1 pyramidal neurons, and immunoblotting was performed to examine the expression of the related proteins. By using the rat model for transient I/R, we demonstrated that puerarin pretreatment significantly increased the travelling distance and number of crossings in the open- and closed-field tests, reduced latency and increased the proportion of distance and time in zone IV in the MWM. The number of live cells in the hippocampus is sharply increased by puerarin pretreatment.We further observed that the levels of phosphorylated Akt1, GSK-3ß and MCL-1were elevated and those of cleaved-caspase-3 were reduced in the puerarin-treatment group. Notably, the PI3K inhibitor LY294002 counteracted all of the effects of puerarin. Our findings suggest that puerarin protects the hippocampus from I/R damage by activating the PI3K/Akt1/GSK-3ß/MCL-1 signaling pathway.

Neuroprotection of Cilostazol against ischemia/reperfusion-induced cognitive deficits through inhibiting JNK3/caspase-3 by enhancing Akt1.

Cilostazol(CTL) is a phosphodiesterase inhibitor, which has been widely used as anti-platelet agent. It also has preventive effects on various central nervous system (CNS) diseases, including ischemic stroke, Parkinson's disease and Alzheimer disease. However, the molecular mechanism underlying the protective effects of CTL is still unclear, and whether CTL can prevent I/R induced cognitive deficit has not been reported. Transient global brain ischemia was induced by 4-vessel occlusion in adult male Sprague-Dawley rats. The open field tasks and Morris water maze were used to assess the effect of CTL on anxiety-like behavioral and cognitive impairment after I/R. Western blotting were performed to examine the expression of related proteins, and HE-staining was used to detect the percentage of neuronal death in the hippocampal CA1 region. Here we found that CTL significantly improved cognitive deficits and the behavior of rats in Morris water maze and open field tasks (P<0.05). HE staining results showed that CTL could significantly protect CA1 neurons against cerebral I/R (P<0.05). Additionally, Akt1 phosphorylation levels were evidently up-regulated (P<0.05), while the activation of JNK3, which is an important contributor to I/R-induced neuron apoptosis, was reduced by CTL after I/R (P<0.05), and caspase-3 levels were also decreased by CTL treatment. Furthermore, all of CTL's protective effects were reversed by LY294002, which is a PI3K/Akt1 inhibitor. Taken together, our results suggest that CTL could protect hippocampal neurons and ameliorate the impairment of learning/memory abilities and locomotor/ exploratory activities in ischemic stroke via a PI3K-Akt1/JNK3/caspase-3 dependent mechanism.

The complete mitochondrial genome of the Alticorpus geoffreyi.

The present study reported the complete mitochondrial genome of Alticorpus geoffreyi for the first time. The mitochondrial genome of A. geoffreyi possesses 16,578 bp in length, involving 22 transfer RNA genes, 2 ribosomal RNA, 13 protein-coding genes and one control region. In addition, its GC content is 45.82% that is similar to that of Astatotilapia calliptera (the GC content of 45.90%). Based on the complete mitochondrial genomes of 14 closely related species, the phylogenetic tree was further made to show their phylogenic relationship. The results will serve as a useful dataset for studying the evolution of Cichlidae mitochondrial genome.

Predictive value of pediatrics end-stage liver disease or model for end-stage liver disease score in the prognosis of pediatric acute liver failure treated with artificial liver support system / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the predictive value of pediatrics end-stage liver disease (PELD) or the model for end-stage liver disease (MELD) in the prognosis of pediatric acute liver failure (PALF) treated with artificial liver support system (ALSS).</p><p><b>METHOD</b>The clinical data of 47 children with acute liver failure seen from August 2008 to July 2013 treated in Children's Hospital, Fudan University were analyzed. Thirty children were treated with ALSS in addition to conventional comprehensive medical treatment (ALSS group). Seventeen children were treated with only conventional comprehensive medical treatment (control group). The main biochemical parameters and coagulation function parameters before and after treatment were compared in the ALSS group and the mortality rates were compared between the two groups. The patients were graded by PELD or MELD when they were hospitalized and the relationship of PELD or MELD scores and mortalities of child patients with the receiver operating characteristic curve (ROC) were analyzed.</p><p><b>RESULT</b>There were significant differences in total bilirubin (TB) ((302 ± 208) vs. (161 ± 129) µmol/L); alanine aminotransferase (ALT) ((161 ± 225) vs. (761 ± 834) U/L); aspartate aminotransferase ( AST) (66 (35, 123 ) vs. 447 (184, 1,129 ) U/L) ; international normalized ratio (INR) ((2.6 ± 1.6) vs. (5.1 ± 4.0)); prothrombin time activity percentage (PTA) ((42 ± 25)% vs. (22 ± 13)%); albumin( ALB) ((35 ± 5) vs. (33 ± 6) g/L) in the ALSS group after treatment. Through the ROC curve analysis, the best PELD/MELD threshold was 25 to predict the patients survival after ALSS therapy, with a sensitivity of 92. 3% , and a specificity of 94.1% at the cutoff point. The area under the ROC curve was 0. 912. The mortality of patients with PELD or MELD score below 25 in the ALSS group (1/13) was lower than the control group (3/4) (P = 0.022), and the mortality of patients with PELD or MELD score over 25 (16/17) was higher than that of the control group (10/13) (P = 0.290).</p><p><b>CONCLUSION</b>PELD or MELD score is a valid index in prognostic evaluation of ALSS therapy, which may provide an evidence for the therapeutic strategies of PALF. Patients with PELD or MELD score below 25 treated with ALSS obtained more benefit.</p>